The invention relates to an apparatus for liquid quenching melt-spun thermoplastic filaments and an apparatus for removing the quenching liquid from the quenched filaments.
In liquid quenching melt-spun thermoplastic filaments it is desirable that the surface of the quenching liquid be in a quiescent state in the area where the freshly spun filaments enter the liquid. Normally, the primary cause of turbulence in the quench tank is not the filaments entering the liquid, but rather the passage of the filaments through the tank and particularly the filaments leaving the liquid. The area where the filaments leave the liquid is usually at the opposite end of the quench tank from where the filaments enter the liquid. However, the turbulence generated by the filaments moving through the tank and leaving the liquid causes waves on the surface of the liquid which travel to the area where the filaments enter the liquid. These waves can splash upon the hot spinning apparatus or spinnerets adversely affecting the uniformity of the filaments and damaging the spinnerets. Also the filaments themselves can be deformed by the direct action of the waves upon them during the quenching process causing irregular drawing of the filaments or the unquenched filaments to fuse together. Consequently to produce uniform liquid quenched filaments it is desirable to maintain the surface of the quenching liquid in a quiescent state.
In addition to problems caused by waves, other problems exist in liquid quenching systems. For example, fluctuation in level of quenching liquid in the quench tank affects the uniformity of the filaments. To reduce this problem the level of quenching liquid is often maintained by using a weir, but due to the meniscus action of most quenching liquids, there is some fluctuation in the quenching liquid level even though a weir is used.
Another problem encountered in liquid quenching systems is removing the liquid from the filaments after the filaments have been quenched. A number of methods have been developed to remove the quench liquid from the filaments, but frequently they abrade, cut or otherwise damage the filaments or affect their uniformity.
It is an object of the invention to provide apparatus to liquid quench melt-spun thermoplastic filaments.
Another object of the invention is to provide a quench tank with a quiescent liquid surface.
Still another object of the invention is to provide a quench tank with a weir which minimizes the meniscus effect of the quenching liquid on the level of quenching liquid in the tank.
Yet another object of the invention is an apparatus for removing quenching liquid from the filaments without damaging or affecting the uniformity of the yarn.